1. Field of the Invention
The present invention relates to an improvement of a method for cleaning a semiconductor silicon wafer, which may be hereinafter referred to as a wafer, simply by using hydrofluoric acid.
2. Description of Related Art
Generally, hydrofluoric acid is used to remove an oxide film on the surface of the wafer, e.g., a thermal oxidation film, a CVD oxide film, a natural oxide film and the like. Because a treatment using hydrofluoric acid makes the surface of the wafer hydrophobic, it raises a problem of easily adhering particles to the surface of the wafer. Reduction of particles adhered to the surface of the wafer is required because such adhesion of particles brings reduction of yield of devices produced.
A method for cleaning the surface of a wafer by rinsing with pure water containing ozone after a cleaning which uses hydrofluoric acid has been suggested as a method for suppressing adhesion of particles to the surface of the wafer after a treatment using hydrofluoric acid, in Japanese Patent Application Laid-Open Publication No. Tokukai-sho 62-198127. Under the present conditions, such a proposed method is not enough to suppress or reduce adhesion of particles to the surface of the wafer after the treatment using hydrofluoric acid.